1. Field of the Invention
The present invention relates to a protection of an oxide superconductor. This type of protection is particularly resistant to water and acids, and therefore, is useful for the protection of semiconductor devices using a superconductor wiring.
2. Description of the Related Art
High temperature superconductors have been developed which include [Y or La (lanthanoids)]-(Ba or Sr)--Cu--O system (T.sub.c =90 K), Bi--Sr--Ca--Cu--O system (T.sub.c =105 K), or Tl--Ba--Ca--Cu--O system (T.sub.c =118 K) oxide superconductors. These superconductors have a high critical temperature, e.g., higher than the boiling point of liquid nitrogen, and have opened the way to a utilization of a superconductor for superconductor magnets, superconductor wiring, SQUID, etc.
The utilization of a superconductor necessitates a processing of the superconductor, per se, or a composite having the superconductor as a constituent component; particularly electronic devices, etc., containing a superconductor are processed with water or an acid such as nitric acid, chloric acid and fluoric acid for cleaning and patterning, etc. Oxide superconductors, however, are highly soluble in water or such acids, and thus may be damaged or the superconductive properties thereof degraded, during a process using water or an acid.
In practice, it has been found difficult to control the composition or structure of an oxide superconductor in an attempt to improve the resistance of the superconductor to water or acids, as superior superconductive properties can be obtained only in a limited composition and structure range. Accordingly, the utilization of an oxide superconductor is prevented due to the difficulty of processing the same.
The main object of the present invention is to provide an oxide superconductor which is protected from the affects of water and acids.